Sealed armature contact relay making process

ABSTRACT

Two magnetizable contact springs are hermetically sealed in a tube to be controlled by magnetic force from the outside. The two contact springs are made from flat strip material by a single stamping operation which produces a substantially rectangular frame structure which is open at one of the short sides where the contact faces are to be located. The frame is joined with, and sealed in, the tube so that the two leg portions of the frame structure extend to the outside of the tube where the frame structure is ultimately cut away to leave two separate terminals. A normally open contact is formed by bending one of the two legs, at least at its top portion, so that it forms a contact face opposite the contact face of the other leg.

United States Patent Fuchs et al.

[54] SEALED ARMATURE CONTACT RELAY MAKING PROCESS I v [72] Inventors:Walter Fuchs; Horst Esche, both of Berlin, Germany [73] Assignee:Deutsche Telephonwerk und Kabelindustrie Aktiengesellschatt, Berlin,Germany [22] Filed: Dec. 30, 1969 [211 Appl. No.: 888,125

A Related U.S. Application Data [63] Continuation of Ser. No. 641,570,May 26, 1967,

abandoned.

[30] Foreign Application Priority Data June 4, 1966 Germany ..D 50248[52] U.S. Cl. ..29/622, 113/119, 335/151, 200/166 C, 200/166 B, 29/602[51] lint. Cl. ..H01h 69/02 [58] Field of Search ..29/622; 335/151-154;113/119; 200/166 C, 166 B [56] References Cited UNITED STATES PATENTS3,128,355 4/1964 Fuller ..29/622 AK, 2r

v FOREIGN PATENTS OR APPLICATIONS 1,184,015 12/1964 Germany ..29/622[57] ABSTRACT Two magnetizable contact springs are hermetically sealedin a tube to be controlled by magnetic force from the outside. The twocontact springs are made from flat strip material by a single stampingoperation which produces a substantially rectangular frame structurewhich is open at one of the short sides where the contact faces are tobe located. The frame is joined with, and sealed in, the tube so thatthe two leg portions of the frame structure extend to the outside of thetube where the frame structure is ultimately cut away to leave twoseparate terminals. A normally open contact is formed by bending one ofthe two legs, at least at its top portion, so that it forms a contactface opposite the contact face of the other leg.

4 Claims, 4 Drawing Figures PATENTEDUEC 5 I972 FIG.4

FIG.3

SEALED ARMATURE CONTACT RELAY MAKING a PROCESS This application is acontinuation of Ser. No. 641,570, filed May 26, 1967, now abandoned.

Our invention relates to sealed tubular contact devices which arecontrollable from the outside by applying an electromagnetic orpermanently magnetic field for actuating a normally open or normallyclosed contact in the tube.

There are known sealed armature contact devices which are fused into atube of glass or other insulating material having a small diameter andwhose contactforming parts consist of magnetizable material in the formof a wire or strip, such as a wire beaten flat. The interior of theprotective tube is evacuated or filled with protective gas. The ends ofthe contact-forming parts extend out of the protective tube and serve asexternally accessible terminals. The other ends of the parts locatedwithin the protective tube are slightly spaced from each other.

According to the method described in the German Pat. 1,060,494, anarmature contact sealed in a protective tube is produced from a wire ofgiven length by bending its contact end to an elongated loop. The freeends of the loop are flattened and overlap each other so as to serve ascontacts which engage each other when a magnetic field is applied.

The German Pat. 1,170,072 discloses a sealed tubular armature contactdevice made of wire whose round cross section is flattened at thecontact locations, and these locations are embossed to enlarge thecontact face and reduce the thickness of the wire material. Since theenlargement of-the contact faces does not involve an increase in themass of the movable parts, the magnetic saturation values remainunchanged and one obtains a larger coupling area for the controllingmagnetic field arranged outside of the protective tube, as compared withthe flattened but unembossed contact wires. The resulting stiffness ofthe magnetizable contact legs, accompanied by a reduction in thickness,af-

fords shortening the contact legs for a given magnetic attraction, orreducing the attractive force required for the switching operation. 1

Another device, shown in the German Pat. 1,090,765, likewise attempts toreduce the space requirements of magnetically controlled contacts andthereby also reducing the over-all dimensions of a relay equipped withsuch contacts. For this purpose the mutually opposite front faces of twoflat contact springs are designed to enter into contact with each other,and at least one of these springs is adapted to move in its plane, underthe effect of the magnetic field, in such a manner that the front faceswill engage each other.

All of the sealed tubular contact devices for magnetic operationheretofore available leave much to be desired. Thus, the elasticstresses imposed upon the cross section of each contact member isconcentrated in a small region where the flat profile merges with theround profile of the wire material. The remaining portion of the contactmember, hardly stressed elastically, greatly reduces by its high inertiathe natural frequency of the member, thus increasing the kinetic energyeffective when the contact member impinges upon the counter contact. Asa result, intensive bouncing is encountered. Such deficiencies aresupposed to be minimized by applying meander-like variations to thecross section of the contact springs. Of disadvantage further is thebilateral embossing process required for some of the other types ofcontact devices, as well as the requirement that the geometric axes ofthe contact springs be offset in parallel relation to each other in theprotective tube in order to have the contact engagement take placeperpendicularly to the direction of spring motion. This aggravatesfusing the contact-making parts together with the glass or similarmaterial of which the protective tube is made.

The German Pat. 1,117,761 describes a sealed tubular and magneticallyactuable contact device whose contacts proper are constituted by thefree ends of two contact springs which are sealed in the protective tubeand are machined from a wire of round cross section by a unilateralpressing or embossing operation. In this device the contact-making faceswiden gradually, and the thickness of the springs gradually decreasesfrom the contact-making side toward the terminals, so that the elasticdeformation of the contact springs, occurring perpendicularly to thecontact faces, will impose an approximately uniform elastic stress uponthe entire length of the springs.

It is an object of our invention to devise a sealed tubular contactdevice with magnetically controllable contact members which avoids theshortcomings of the devices of this general type heretofore-availableand which also affords producing such sealed devices by a method that issimpler to apply and that also reduces the cost of materials and laborrequired for the manufacture of the device.

Another, more specific object of the invention is to provide a novelcontact device and a method of its manufacture that secure a minimumdanger of bouncing or arcing at the contacts even if the device is givenreduced dimensions in comparison with known devices of the same voltageor current rating.

Another, conjoint object is to secure in a simple manner a distributionof the elastic stress, caused by magnetic actuation, over the entirecross section and substantially the entire length of each contactmember.

To achieve these objects, and in accordance with a feature of ourinvention, we produce the two cooperating contact members of asealedtubular and magnetically actuable contact device from a flatmagnetizable sheet or strip material, preferably in a single step ofstamping or other suitable shaping operation, by first shaping agenerally frame-shaped rectangular structure that is open at one of theshort sides where ultimately the contact faces are to be constituted. Wethen bend only one leg portion of such an open frame structure so as'toplace the contact-forming end of that leg portion into cooperativeopposition to the adjacent end of the other contact member. Subsequentlywe hermetically seal this structure into the protective tube but let theclosed narrow side of the frame structure remain outside one of the endsof the tube, while the contactforrning localities are located inside thetube, preferably near the other end thereof.

Relative to this and other features of out invention, reference shouldbe had to the claims annexed hereto, as well as to the accompanyingdrawings in which embodiments of sealed tubular contact devicesaccording to the invention are illustrated by way of example.

FIG. 1 shows, partially in section, a lateral view of one form of asealed tubular contact device.

FIG. 2 illustrates, also in partial section, the same device turned 90about its longitudinal axis.

FIG. 3 is a plan view of the stamping cut of which the contact membersproper are made; and

FIG. 4 is a plan view of another embodiment of a stamping suitable forproducing the contact members of tubular devices according to theinvention.

The sealed tubular contact device according to FIGS. 1 and 2 comprises apreferably flat protective tube 1 of glass or other non-metallic andnon-magnetic material. The contact system 2 in the embodiment of FIGS. 1and 2 constitutes a normally open relay con tact. The system is made ofa single frame-shaped blank stamped out of magnetic sheet or stripmaterial to the rectangular shape shown in FIG. 3 or FIG. 4. As will bedescribed, the contact-system 2 results from such a blank by applying asingle bending operation. The contact system 2 is fused into theprotective tube 1 in such a position that the contact-forming ends ofthe open frame structure are located inside the tube, preferably in thevicinity of one tube end. The other narrow side of the frame structure,remaining closed as shown in FIGS. 3 and 4, protrudes out of the fusedtube 1. Ultimately the closed end of the frame structure is cutawayalong the line 11 in FIG. 1. The two shanks or legs which then remain ofthe original frame structure thus constitute electric terminals 4 and 5which form a glassto-metal seal with the protective tube and areaccessible from the outside. The interior of the protective tube 1 isevacuated or filled with inert or noble gas such as argon.

Referring to the stamped or cut blanks of flat magnetizable and elasticmaterial shown in FIGS. 3 and 4, it will be seen that each of themessentially constitutes an elongated rectangular frame which is open atone of its narrow sides. In both embodiments, the electric contactlocalities 21, 22 (FIG. 3) or 31, 32 (FIG. 4) are adjacent to the openends of the frame structure. Preferably the contact faces are coatedwith silver or other noble metal, at least at the side facing theopposite contact and entering into engagement therewith when the contactis closed. 1

In the embodiment of FIG. 3, the open frame structure is composed of aU-shaped portion whose respective legs 24 and 25 are unequal in length.The longer leg 25 has a T-shaped top portion whose trunk is parallel tothe bottom portion 23 of the U-shape. The bottom portion 23 may have thesame width as the respective contact faces 21 and 22. The legs 24 and 25of unequal length have different configurations in the longitudinaldirection of the legs. That 'is, according to FIG. 3 the two legs areprovided with lateral recesses which are longitudinally offset from eachother. For example, the recess 31 of leg 24 is displaced relative to therecess 311 of leg 25 by an amount designated by 3. As a result, each ofthe two spring legs 24, 25 has a natural frequency differing from anyeven multiple of the other. This is particularly advantageous forpreventing contact bouncing when the normally open contact is beingactuated.

For converting the blank according to FIG. 3 to a contact system asshown in FIGS. 1 and 2, the T-shaped portion on top of leg 25 must bebent approximately 180 in the vicinity of the contact locality 21 andalong the dot-and-dash line 27. The bending deformation, of course, mustbe permanent. Care must be taken that the two contact faces 21 and 22will overlap a sufficient extent and that the spacing shown at 6 in FIG.2 remains preserved between the legs 24 and 25, as well as between theappertaining contact faces 21 and 22. When a magnetic field is applied,the elastic legs or shanks 24 and 25 attract each other so that thecontact faces 21 and 22 are firmly pressed against each other. Whenthereafter the magnetic field is removed, the contact members return totheir respective starting positions, thus opening the contact betweenfaces 21 and 22. Since the working gap 6 can be correctly determined bythe manufacturing operation, such as with the aid of a jig, no furtheradjustment, as a rule, is needed for properly setting the normally opencontact.

The open frame structure in the embodiment according to FIG. 4 alsocomprises a U-shaped portion whose legs or shanks 43 and 44 are unequalin length. The longer leg 44 has a T-shaped top portion whose trunk isparallel to the bottom portion 45 of the frame structure and which formsa contact face at 41. In this embodiment, however, the base of theU-shaped bottom portion is longer than the T-shaped portion; and the leg43 is to be bent about along the dot-and-dash line 46 which extendsparallel to the legs and through the bottom portion 45 of the U-shape.Due to such bending, the contact faces 41 and 42 become located oppositeeach other and will overlap while preserving the desired contact spacebetween each other. For securing the spacing necessary for a normallyopen contact, the bending edge 46 must be spaced from the leg 43 anamount substantially equal to the one designated by 6 in FIG. 2. Thatis, after bending the leg 43, it will extend parallel to the plane ofthe base portion 45 but spaced therefrom a distance corresponding to theone denoted by 6. a

When producing the contact system 2 it is preferable to perform thestamping according to FIG. 3 or FIG. 4 in such a manner that uponcompletion of the bending operation the burr side of the open framestructure will not be located in the direction of the contact-makingfaces 21, 22 or 41, 42. That is, any burrs should face outwardly so thatthey are harmless. This avoids the necessity of deburring so that themanufacturing process is reduced to a minimum of steps.

To those skilled in the art it will be obvious from a study of thisdisclosure that our invention is amenable v to various modificationswith respect to type, size and configuration of the contacts or othercomponents, and hence may be given embodiments other than particularlyillustrated and described herein, without departing from the essentialfeatures of our invention and within the scope of the claims annexedhereto.

We claim:

1. In a method of producing a sealed contact device which comprisesstamping from a flat strip of magnetizable elastic material havingopposite planar faces a substantially rectangular frame structure formedof a substantially U-shaped and a substantially T-shaped portion, saidU-shaped portion including a short leg and a pair of opposite longlegsconnected to said short leg, one of said long legs being longer thanthe other, and said T-shaped portion including a trunk part connected tosaid longer long leg and extending substantially parallel to said shortleg, said T-shaped portion being formed with an end portion spaced fromthe shorter long leg and extending in the same direction and laterallyadjacent an end portion of the shorter long leg, bending one of saidU-shaped and T-shaped portions back upon itself to a permanent positionin which the end portion of said T-shaped portion and the end portion ofsaid shorter long leg overlap one another in mutually spacedrelationship and have mutually opposing contact surfaces, respectively,that are from the same planar face of the flat strip and form a normallyopen contact with each other, inserting part of the structure includingthe normally open contact into an elongated protective tube through anopen end of the latter, so that the remainder of the structure includingsaid short leg is located outside the open end of the tube, and sealingthe open end of the tube.

2. The method according to claim 1, wherein said bending issubstantially limited to the end portion of said T-shaped portion and isgiven an angular amount of approximately the bending being done about aline parallel to the longitudinal direction of said frame structure.

3. The method according to claim 1, which comprises bending said shorterlong leg about 180 about a line extending parallel to the longitudinaldirection of the frame structure and through said short leg of the framestructure.

4. The method according to claim 1, which comprises cutting the shortleg away from the frame structure for separating the outside ends ofsaid long legs,

respectively, from one another to thereby form respective terminals.

1. In a method of producing a sealed contact device which comprisesstamping from a flat strip of magnetizable elastic material havingopposite planar faces a substantially rectangular frame structure formedof a substantially U-shaped and a substantially T-shaped portion, saidU-shaped portion including a short leg and a pair of opposite long legsconnected to said short leg, one of said long legs being longer than theother, and said T-shaped portion including a trunk part connected tosaid longer long leg and extending substantially parallel to said shortleg, said T-shaped portion being formed with an end portion spaced fromthe shorter long leg and extending in the same direction and laterallyadjacent an end portion of the shorter long leg, bending one of saidU-shaped and T-shaped portions back upon itself to a permanent positionin which the end portion of said T-shaped portion and the end portion ofsaid shorter long leg overlap one another in mutually spacedrelationship and have mutually opposing contact surfaces, respectively,that are from the same planar face of the flat strip and form a normallyopen contact with each other, inserting part of the structure includingthe normally open contact into an elongated protective tube through anopen end of the latter, so that the remainder of the structure includingsaid short leg is located outside the open end of the tube, and sealingthe open end of the tube.
 2. The method according to claim 1, whereinsaid bending is substantially limiTed to the end portion of saidT-shaped portion and is given an angular amount of approximately 180*,the bending being done about a line parallel to the longitudinaldirection of said frame structure.
 3. The method according to claim 1,which comprises bending said shorter long leg about 180* about a lineextending parallel to the longitudinal direction of the frame structureand through said short leg of the frame structure.
 4. The methodaccording to claim 1, which comprises cutting the short leg away fromthe frame structure for separating the outside ends of said long legs,respectively, from one another to thereby form respective terminals.